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Bonding Process for NTC Thermistor
2018/05/24 05:05:32

Bonding Process for NTC Thermistor

Step 1: Expanding crystal. The expansion machine is used to evenly expand the entire LED wafer film provided by the manufacturer, so that the LED crystal grains that are closely arranged on the surface of the film are pulled apart to facilitate the thorn crystal.


Step 2: Adhesive. The expanded crystal expansion ring is placed on the surface of the back adhesive machine where the silver paste layer has been scraped. The silver paste is backed and the silver paste is spotted. Suitable for bulk LED chips. Use a dispenser to spot the appropriate amount of silver paste on the PCB.


Step 3: Put the expanded crystal ring prepared with silver paste into the gill frame, and the operator punctures the LED chip with a stab pen on the PCB printed circuit board under the microscope.


Step 4: Place the complete crystal's PCB printed circuit board in the heat cycle oven and stand for a while at constant temperature, after waiting for silver slurry curing out (not for a long time, or LED chip coating will discolor yellowish, oxidizing, cause bonding difficulties).If there are LED chips, the above steps are required. If only IC chip bonding, the above steps are cancelled.


Step 5: Paste the chip. Use the dispensing machine to place a suitable amount of red glue (or black glue) on the PCB's IC board position, and then use an antistatic device (vacuum suction pen or sub) to place the bare IC chip correctly on the red or black glue.


Step 6: Drying. Place the sticky die in a thermal cycle oven and place it on a large flat heating plate for a while at a constant temperature. It can also be cured naturally (for a long time).


Step 7: Bonding (wire bonding). An aluminum wire bonding machine is used to bridge the wafer (LED die or IC chip) and the corresponding pad aluminum wire on the PCB.


Step 8: Pretest. Use dedicated inspection tools (different equipment for different uses of COB, simple high-precision regulated power supply) to detect the COB board and rework the failed board.


Step 9: Dispensing. The dispensing machine is used to place a suitable amount of AB glue on the bonded LED die, and the IC is encapsulated with vinyl, and then the exterior packaging is performed according to customer requirements.


Step 10: Curing. Put the sealed PCB printed circuit board into a heat cycle oven and keep it at a constant temperature. According to the requirements, different drying time can be set.


Step 11: Final test. The encapsulated PCB printed circuit board will be tested for electrical performance using dedicated inspection tools to distinguish between good and bad.

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